ZF front axles - Bearings and transmission shafts

On tractors, the front bearings, located on the cast-iron stand, support the two pivots of the ZF front axle. The 4WD transmission shaftline comprises two shafts, the straight shaft (1) and the universal shaft (1A). They are linked to the 4WD and the ZF front axle housing (52) by splined sleeve (3) and the universal joint spiders (9). This transmission line is supported by bearing (6) and bearing block (5) fitted beneath the lower housing at the rear of the engine.

Parts list - Overall view
(1) Bolt (2) Front bearing (3) Mecanindus locating pin (4) Washer (6) Rear bearing (8) Seal (9) Seal (10) Bush (11) Seal (12) Bolt (14) Bush (15) Main bearing stand (16) Bolt (17) Grease nipples (18) Grease nipples (19) Cover (20) Stop washer (21) Locating pins (22) Washer (23) Nuts (52) Axle housing

Disassembling and reassembling 4WD transmission shafts and universal joint spiders

Universal shaft
Chock the front wheels and put on the handbrake. Remove the front guard (2A). Remove universal shaft (1A) with its spiders.

- The universal shaft and spiders form a complete assembly referenced in the spare parts catalogue. Reinstall the shaft.
Raise the front wheels (optional). Fix the spiders on sleeve (4) and plate (7) using bolts (8) previously lightly smeared with Loctite 241 or its equivalent and tightened to a torque of 61 - 81 Nm. Using a grease gun, grease sleeve (4). Reinstall the front guard (2A).

Straight shaft
Remove the front guard and the universal shaft and carry out operations.
Remove the rear guard (2).
Spread apart the rubber protectors on sleeve (3). Take out the bolt located in the centre of the sleeve and slide the latter along straight shaft (1) towards the front of the tractor.
Uncouple and remove the shaft, sleeve (3) and bearing (5) assembly.

Inspect the components. Replace any parts found to be defective.
Install the shaft and sleeve assembly. Assemble the central bearing.
Tighten the bolts of bearing (5) and the central bolt of sleeve (3).

Position the straight shaft.
- The rotating shaft turns bearing (6) located in bearing (5) by means of bolts V.
Lightly smear bolts V with Loctite 542 or its equivalent and tighten them in order to obtain a space between the rear end of the shaft and the central bolt on sleeve (3). Place the rubber protectors on the sleeve.
Using a grease gun, grease sleeve (3). Install guard (2).
Install the universal shaft (1A) and refit the front guard (2A).

Removing and install the bearings

Remove the front weights and centre weights (if fitted). Immobilise the tractor by putting on the handbrake and placing chocks on either side of the rear wheels. Remove the front guard and disassemble the universal shaft (1A). Raise the front of the tractor using an appropriate jack positioned in the axis of the axle housing. Take off the wheels. Position an axle stand under the lower part of the engine sump.
Locate the hose unions and disconnect them from the steering rams.
Sling the front axle using appropriate straps.

Take off grease nipple (17). Remove bolts (1), the bearing stand (2) and seal (9). Unscrew nuts (23) and recover the washers (22).
Remove the front axle with bearing stand (6).

Separate the bearing stand from the ZF front axle. Recover seal (8) and washer (4).
- The Mecanindus pin (3) is force fitted in housing (52).

Slide washer (4) on the axle pivot with the hole facing the Mecanindus pin (3).
Position new seals (8) (9) on the axle pivots turning the lip towards their respective stands.
Sling the front axle. Install the front axle and stands assembly.
Place the stands on the main stand. Install the bolts and washers and tighten the nuts (23) lightly smeared with Loctite 270 or its equivalent to a torque of 540 - 610 Nm.
Push bearing stand (2) towards axle housing (52) in order to obtain the minimum clearance possible between the bearing stands and housing.
Install the washers and tighten bolts (1) previously lightly smeared with Loctite 270 or its equivalent to a torque of 480 - 640 Nm.
Check for the presence of grease nipples on cover (19) and on each bearing.
Reconnect the hoses to the steering ram.
Reinstall the wheels. Remove the axle stand. Tighten the wheel nuts to a torque of 640 - 680 Nm. Reinstall the centre weight and front weights (depending on options).
Reinstall the universal shaft and guard.
Remove the chocks and take off the handbrake.
Using a grease gun, grease bushes (10) (14) in the bearing stands.

Replacing bushes and seal

Remove the bearing stands.
Front bearing 
Take out bolts (16), remove cover (19) and stop washer (20). Extract and discard bush (14) of bearing stand (2).

Rear bearing 
Mark the position of the dust seal (11). Extract and discard the latter as well as bush (10).

Clean and inspect the components. Replace any parts found to be defective. Check that the grease channels are not obstructed.

Rear bearing 
Using a press and an appropriate fixture, insert bush (10) home against the shoulder of bearing stand (6), with the oblong ports O facing upwards and communicating with the bearing lubricating channel.
Using a press and an appropriate fixture, insert the dust seal (11) in the correct direction, abutting against the shoulder of bearing stand (6).

Front bearing 
Using a press and an appropriate fixture, insert bush (14) flush with face F of bearing stand (2) and with the oblong ports facing upwards and communicating with the lubricating channel of bearing stand (2).
Reinstall the stop washer (20).

- The stop washer has ridges that allow the passage of grease for the lubrication of the bearing block.
Install cover (19) on bearing block holder (2) and tighten bolts (16) to a torque of 90 - 120 Nm. Install the bearing stands.